Första bilden av Philae på kometens yta. Foto: ESA
The first picture of the Philae lander on the comet's surface. Photo: ESA

Space Agency: Philae lander now on comet, kind of

"We have already learned the surface is stable"
6:12 min

Yesterday, it was success for the European Space Agency when the Philae robotic lander set foot on comet 67P, but scientists say they are not quite sure exactly where it landed.

The probe successfully separated from its mother-ship Rosetta, before heading to the surface of the comet. After spending the night analysing the data sent by the lander, mission specialists say it seems it first bounced off the surface of the comet and back out into space before touching down two more times. It is now stable on the surface, but only two of the lander's three legs have contact with the ground.

It also seems to be next to a cliff wall, or the edge of a crater, which puts it in a shadow. The fact that harpoons and drills on the landing gear also failed to work properly means that any attempt to do the more mechanical experiments, like drilling into the comet, could push the lander off the surface again.

Anders Eriksson from the Swedish Institute of Space Physics has been working with gas sensors on Rosetta, and speaking to Radio Sweden says despite the hiccups it is good to see that Philae actually landed.

"It's good to see that the lander is alive, that it has landed, although it certainly had an interesting ride there", he says, "if you compare to the ideal state, which would actually have been that it stayed where it first touched down, which was pretty much in the bullseye of where they were aiming for, then of course it's not as good a place because the illumination here is worse."

That could be problematic as the lander needs sunlight to recharge its batteries. Having no sunlight could shorten the mission considerably as the batteries die, but Eriksson says that that possibility was also part of the plan.

"The lander mission was designed to do the science it should during the lifetime of the battery, so in that sense they can certainly do great", he adds.

But what does it look like on the comet, what would any human piggybacking on the lander see and feel?

"Cold temperatures, far below zero centigrade", Eriksson says, "extreme variations between day and night, basically as soon as the sun sets on the comet then it is deeply, deeply cold. Illumination is weak, we are three times as far from the sun as Earth is, so it's a bit like a Swedish cloudy November day."

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